1. Field of the Invention
This invention relates to a control apparatus, such as an entry system of a vehicle, for checking an authentication code for validity (so-called ID authentication), etc., for example, based on radio communications between a portable machine and a main unit machine, and for controlling machines, units, systems, etc., installed in the vehicle without requiring cumbersome operation of the operator.
2. Description of the Related Art
As a system containing this kind of control apparatus, for example, a keyless entry system of a vehicle coming into wide spread use in recent years has been available. This keyless entry system comprises a portable machine that can be carried by the user and a main unit machine (in this case, vehicle-installed machine) installed in a controlled object (in this case, vehicle). In keyless entry system, authentication code is checked for validity by radio communications between them and predetermined operation (unlocking or locking operation) of the controlled object (in this case, vehicle door locking) is accomplished under the control of the main unit machine provided that the authentication code is valid.
An early-type and general system of such a system has a configuration wherein the user operates a specific button, etc., placed on a portable machine, thereby radio-transmitting a specific operation signal containing an authentication code (for example, vehicle door unlocking command) from the portable machine, and a main unit machine receives the signal and checks that the authentication code contained in the received signal corresponds to the authentication code preset in the main unit machine, then performs predetermined output for controlling a predetermined controlled object (for example, control signal output for unlocking vehicle doors). Namely, the system provides a one-way communication system of conducting only one-way communications from the portable machine (in this case, transmitter) to the main unit machine (in this case, receiver)
However, in such a one-way communication system, the portable machine needs to be driven only with an installed battery, and it is impossible to output a signal containing the authentication code all the time because of consumption of the battery. Thus, as described above, a signal must always be transmitted with some operation of the user as a trigger (namely, it always becomes necessary for the user to perform some intentional operation); the system involves a limit to enhance the convenience of the user.
Then, in recent years, a more advanced system for conducting two-way communications containing electric power transmission between a portable machine and a main unit machine has been proposed and partially has been put to use. The system executes necessary check for validity while suppressing consumption of the power of the portable machine and then operating a controlled object.
For example, as a keyless entry system of a vehicle, a two-way communication system comes along, wherein a portable machine, which enters a communication-possible range, receives electric power transmission in non-contact from a main unit machine, thereby being started with the electric power transmission as a start signal, and transmits a signal containing an authentication code to the main unit machine while electric power required after the portable machine is started is also provided by the electric power transmission depending on the situation.
The two-way communication system makes it possible to automatically transmit the signal containing the authentication code to the main unit machine with the start caused by the power transmission as a trigger, so that predetermined operation of the controlled target can be accomplished without performing any operation of the user depending on the situation. For example, with an entry system of a vehicle, if the user carrying a portable machine simply approaches a door of a specific vehicle installing a main unit machine corresponding to the portable machine, the above-mentioned two-way communications can be established and an unlocking command can be automatically output to the lock of the locked door for automatically unlocking the vehicle doors. The more convenient entry system for enabling the vehicle doors to be unlocked or locked basically without requiring intentional operation of the user is called a smart entry system (or a hand-free entry system), etc., as a development model of a general keyless entry system. The market needs for such a smart entry system, etc., grow as an entry system enhancing the commodity product value of the vehicle installing the entry system.
By the way, antennas described in Japanese Patent Unexamined Publication No. Hei. 9-310548 and Japanese Patent Unexamined Publication No. Hei. 10-53071 have been known as an antenna of a main unit machine in such a system. That is, a rod antenna is built in a column part of a sun visor of an automobile or a room mirror attachment part for the purpose of maintaining a good directivity of the antenna.
However, the antennas of the main unit machines as described above involve the following problems:
It is difficult to provide a properly wide communication-possible range thoroughly (with no partial blind region) while transmission output is reduced to a minimum. Thus, there is a high possibility of occurrence of the following problem: Although the user carrying a portable machine lies in the same degree of the distance range from a vehicle (or exists in the vehicle), radio communications become impossible and predetermined control processing cannot be carried out depending on the existence position of the portable machine (particularly, position in the floor direction of the vehicle).
For example, advanced processing for determining where the portable machine exists based on whether or not radio communications are established cannot precisely be performed.
Particularly to put an advanced system such as the above-described smart entry system to use, the range in which radio communications (particularly, transmission and reception of power transmission as a start signal) are possible between the main unit machine and the portable machine (namely, the communication-possible range) needs to be set with good accuracy (or it may be preferred that the communication-possible range can be set with good accuracy). If a determination as to whether the portable machine (or the user carrying the portable machine) exists inside or outside a position a predetermined distance from the surroundings of the vehicle or whether or not the portable machine exists in the vehicle (namely, a portable machine search function of determining where the portable machine exists) can be accurately made based on whether or not radio communications are established, for example, the operation of automatically locking unlocked doors if the user carrying the portable machine simply leaves the vehicle a predetermined distance or more, the operation of enabling engine start if the user carrying the portable machine simply rides in the vehicle, or the like is made possible precisely without installing any separate expensive sensor, etc.
However, with the antennas in the related arts as described above, it would become difficult to, for example, set a communication-possible range for in-vehicle communications (particularly, transmission/reception-possible range of start signal) thoroughly in a sufficient wide range in the vehicle and set a communication-possible range for out-of-vehicle communications (particularly, transmission/reception-possible range of start signal) precisely in a predetermined range surrounding the vehicle (at least it would become difficult to set the range with one or several antennas). For example, as for the communication-possible range for in-vehicle communications, if only one antenna in the related art is placed in a vehicle, a communication-impossible region (blind region) of at least a start signal occurs in most portions in the vehicle. For example, if transmission output of the main unit machine is raised attempting to eliminate the blind regions, power consumption is increased and in addition, the communication-possible range is widened more than necessary at points where directivity is strong, and radio wave is output to the outside of the vehicle via a non-conductive portion (for example, window portion of vehicle), whereby the accuracy of the portable machine search function also worsens and the crime prevention of code theft is degraded because of radio wave leakage to the outside of the vehicle. If a plurality of antennas are placed at points in the vehicle for attempting to solve the problems, a large number of antennas become necessary, increasing the costs drastically.
According to the research of the inventor et. al, the reasons why it is hard to set a proper communication-possible range with the antennas in the related are as follows: First, the antennas attach importance to directivity. Second, as the antenna placement position, the antenna is built in a position easily affected by the vehicle body (metal portion) such as a column part of a sun visor or a room mirror attachment part as mentioned above.
It is therefore an object of the invention to provide a communication-type control apparatus for making it possible to solve problems concerning antennas as described above and set a proper communication-possible range while suppressing an increase in power consumption and apparatus costs, thereby more enhancing the reliability of control or the convenience of the user.
According to the invention, there is provided a control apparatus comprising:
a portable machine that can be carried by the user; and
a main unit machine being installed in a vehicle for executing control processing to accomplish predetermined operation of an object installed in the vehicle in response to the result of radio communications conducted with the portable machine. In the control apparatus, a radio communication antenna of the main unit machine is shaped like a coil and is placed so that an axial direction of the antenna becomes at right angle to a floor of the vehicle.
According to the invention, it is made possible to set the communication-possible range to an exceptionally wide, proper range (less blind regions as a whole) although the number of antennas, the antenna placement position, or the transmission output is the same as verified from the test results described later.
Thus, the possibility of occurrence of the problem wherein although the user carrying the portable machine lies in the same degree of the distance range from the vehicle (or exists in the vehicle), radio communications become impossible and the predetermined control processing is not executed depending on the position of the portable machine (particularly, position in the floor direction of the vehicle) can be decreased (namely, the operation reliability can be enhanced) without increasing power consumption or costs or involving the detrimental effects caused by unnecessary enlarging of the communication-possible range (the fear of having the authentication code contained in a radio signal stolen because the communication-possible range is unnecessarily spread or the like).
The term xe2x80x9cvehiclexe2x80x9d mentioned here includes an automobile, a small-sized airplane, etc., for example. The expression xe2x80x9cobject installed in the vehiclexe2x80x9d can be a door lock, a drive source of an engine, a motor, etc., a drive mechanism of a transmission, etc., an air conditioner, an audio set, a navigation system, illumination, etc., for example.
The term xe2x80x9cradio communicationsxe2x80x9d mean communications using electromagnetic waves. The electromagnetic waves mentioned here also include infrared rays, etc., in addition to at least radio waves in the narrow sense.
The expression xe2x80x9cexecuting control processing to accomplish predetermined operation of an object installed in the vehicle in response to the result of radio communications conductedxe2x80x9d can be a mode of outputting a control signal for simply unlocking a door following a command transmitted in one way from the portable machine, for example, and a mode of checking the authentication code transmitted in one way from the portable machine for validity before outputting a control signal for unlocking a door following a command transmitted in one way from the portable machine. It can also be a mode in which a portable machine start signal is transmitted from the main unit machine, the portable machine started upon reception of the start signal returns an answer signal, and the main unit machine, which receives the answer signal, checks the authentication code contained in the answer signal for validity before outputting a control signal for unlocking a locked door.
The expression xe2x80x9cfloor of vehiclexe2x80x9d means the floor of the cabin (living space) of the vehicle, and the expression xe2x80x9cright angle to floor of vehiclexe2x80x9d means a direction almost at right angle to the plane along the average plane direction of the whole floor (normally, plane parallel with the ground surface); a reasonable error from the strict right angle is contained as long as the communication-possible range can be set sufficiently wide and proper.
In a preferred form of the invention, as the radio communication antenna of the main unit machine, one or more in-vehicle communication antennas for conducting radio communications with the portable machine existing in the vehicle are placed near the center in a floor direction in the vehicle.
Such a composition makes it possible to set the communication-possible range with the portable machine in the vehicle to a wide range containing the corners in the vehicle while reducing transmission output to a minimum, and at most two in-vehicle communication antennas for the purpose may be placed.
Thus, the most of the above-described advantages of the invention can be made concerning radio communications made effective particularly when the portable machine exists in the vehicle. This means that it is made possible to enhance the reliability of the control operation based on radio communications made effective with the portable machine in the vehicle without increasing power consumption, costs, etc.
Preferably, the in-vehicle communication antenna is placed reasonably above the floor to decrease the effect from the floor of the vehicle.
In a preferred form of the invention, the main unit machine has a portable machine search function of determining where the portable machine exists depending on whether or not the radio communications with the portable machine are established.
Such a configuration makes it possible to precisely determine where the portable machine exists without the need for an additional sensor, and the portable machine search function important for an advanced system such as a smart entry system can also be realized with high reliability without increasing power consumption, costs, etc.
The portable machine search function can be provided by processing of a control circuit including a microcomputer contained in the main unit machine, for example.
In the control apparatus of the invention, the object installed in the vehicle may be a lock for locking or unlocking a door of the vehicle and the control processing may be control signal output for accomplishing the locking or unlocking operation of the lock.
In this case, the most of the above-described advantages of the invention (enhancement of the operation reliability, suppression of power consumption and costs, etc.,) can be made in a vehicle unlocking system (namely, entry system).
The main unit machine may have an in-vehicle communication antenna for conducting radio communications with the portable machine existing in the vehicle as the radio communication antenna and a portable machine search function of determining at least whether the portable machine exists inside or outside the vehicle depending on whether or not the communications with the portable machine through the in-vehicle communication antenna are established. The main unit machine may execute the control signal output for accomplishing the locking operation of the lock only if it is determined by the portable machine search function that the portable machine does not exist in the vehicle.
In such a configuration, if the portable machine or the user carrying it exists in the vehicle, the locking operation of the lock mentioned above (for example, automatic locking operation performed by the control apparatus, etc.,) is not executed, so that the portable machine or the user carrying it can be prevented from being locked into the vehicle with the above-described advantage of the invention. This means that the function of preventing the portable machine or the user carrying from being locked into the vehicle in the locking operation of the entry system can be realized with high reliability without increasing power consumption, costs, etc.
The main unit machine of the invention may have a portable machine search function of determining at least whether or not the portable machine is away from the vehicle exceeding a communication-possible range depending on whether or not the radio communications with the portable machine are established, wherein if it is determined by the portable machine search function that the portable machine is away from the vehicle exceeding the communication-possible range, the main unit machine may check that another necessary condition holds as required before executing the control signal output for accomplishing the locking operation of the lock.
In such a configuration, if the user carrying a predetermined portable machine gets off the vehicle and is away from the vehicle at a predetermined distance, the fact is determined by the portable machine search function and if another necessary condition holds, the locking operation of the lock of the vehicle is automatically executed. Therefore, the user can lock the doors of the vehicle simply by doing the natural action of getting off and being away from the vehicle without performing any intentional locking operation. Thus, the advantage of making it possible to accomplish the exit operation of a smart entry system can be produced with the above-described advantage of the invention. This means that the exit operation of the smart entry system can be realized with high reliability without increasing power consumption, costs, etc.
The expression xe2x80x9canother necessary conditionxe2x80x9d can be, for example, that the lock be in an unlocked state or that the authentication code of the portable machine be determined valid by radio communications conducted before it is determined that the portable machine is away from the vehicle exceeding the communication-possible range.
The control processing may be signal output or data setting operation for enabling the operation of the object installed in the vehicle, or signal output for giving an instruction to operate the object installed in the vehicle.
In this case, a control system of the object installed in the vehicle by radio communications is provided and in such a system, the most of the above-described advantages of the invention (enhancement of the operation reliability, suppression of power consumption and costs, etc.,) can be made.
The expression xe2x80x9cdata setting operation for enabling the operation of the object installed in the vehiclexe2x80x9d means internal processing of setting a flag for enabling the operation of the object installed in the vehicle in information processing of the main unit machine, for example.
The main unit machine of the invention may have an in-vehicle communication antenna for conducting radio communications with the portable machine existing in the vehicle as the radio communication antenna and a portable machine search function of determining at least whether the portable machine exists inside or outside the vehicle depending on whether or not the communications with the portable machine through the in-vehicle communication antenna are established, and the main unit machine may execute the signal output or data setting operation for enabling the operation of the object installed in the vehicle, or the signal output for giving an instruction to operate the object installed in the vehicle only if it is determined by the portable machine search function that the portable machine exists in the vehicle.
In such a configuration, if the portable machine or the user carrying it does not exist in the vehicle, the operation of the object installed in the vehicle is not enabled or an instruction to operate the object installed in the vehicle is not given. Thus, a problem of operating the object installed in the vehicle illegally or by mistake although the portable machine does not exist in the vehicle (for example, a problem of starting the engine of an unattended automobile and degrading safety of the surroundings) can be circumvented with the above-described advantage of the invention. This means that the function of preventing malfunction or illegal operation in the control system of the object installed in the vehicle by radio communications can be realized with high reliability without increasing power consumption, costs, etc.